Preheat the oven to 190C/gas 5/fan 170. Arrange the chicken in a shallow ovenproof dish. Mix together the honey, lemon zest and juice, oil, salt and pepper, then pour over the chicken breasts and turn them around until well coated.
Roast the chicken breasts for 40-45 minutes, turning them halfway through the cooking time, and basting occasionally, until they are golden brown and shiny and the marinade has almost evaporated. Leave to cool, then wrap in foil and chill until ready to eat. (The chicken may now be frozen for up to 1 month. Defrost before serving.)
On the day, spread the lettuce over a large platter, tearing up any large leaves. Slice the chicken breasts, keeping them together, then arrange over the lettuce.